Emergency vehicles, such as police cars and ambulances, often have warning or alert systems mounted on them to warn individuals in the vicinity that the emergency vehicle is approaching, or to alert individuals of a dangerous situation. Typically, these systems include a siren to provide an audible warning, and a lighting system typically centered atop the emergency vehicle to provide a visual flashing light warning.
Often, police officers or emergency medical technicians (EMTs) work dangerously close to active vehicle traffic lanes. The situation is made even more dangerous by the unconscious tendency of drivers to steer or drift toward the object at which they are looking. Especially when it is dark, the most noticeable distraction may be the emergency lights atop the respondent's emergency vehicle.